Pneumatic spring.



E. D. FOSTER.

PNEUMATIC SPR-ING.

APPLlcATloN man Aus. la. 1914.

Patented Oct. 9, 1917.

.ERNEST D. l:F.osalsrt, or Los Yairennns` caninoruirfr`A,v Ass'rsnoia, ,sy `ivi,asuE Assiett- PNEIMATI SPRING.. y

To all whomvl may concern: v Y

,'Be it-known thatiI, ERNEST D. FOSTER, citizen of the United States, residingatfIos Angeles, in the county'ofJ Los-Angeles, and State of California, -have invented' certain new and useful Improvements in Pneumatic Springs, of which the following' is a speciflcation.

My invention relates to an improvement in pneumatic springs, and more particularly to such springs as are intended to be used upon vehicles to relieve the shock to the rider.

The object of this invention is to provide a pneumatic spring in which the structure is substantial, readily attached, and when attached, gives a highly efficient cushioning action without a noticeable rebound.

This invention relates to certain other novel features of construction and combinations of parts which will be hereinafter fully described and pointed out in the claims.

In the accompanying drawings:

Figure l is a vertical sectional view to show one form which the invention may take, and

Fig. 2 is a similar view to show a slightlyI modified form.

A top-plate A is flanged at its edge as at 1 to form a face groove, and a flexible casing B is secured in this groove by means of .a collar 2, which is held in place by bolts 3, 3. The casing B is made semispherical or conoid in form, and is preferably of fabric reinforced rubber. A liningplate 4L is pref-v erably received within the top plate A, and has a flange on the edge thereof which lits tight against the casing B.

A stem C is bifurcated to fit'over the part of the member to which the spring is to be attached in its lower part, and a bolt 6 is passed from the inside of the casing B through an opening in this casing, and is screwed into the stem C.

It is preferable that this connection between the stem C and the casing B be formed to be fluid-tight. The bolt 6 has a passage 7 therethrough, in which the upper threaded end of a nipple 9 is screwed, the latter forming a continuation of the bolt. An air tank D is provided with an opening 11 through which it may be filled, and a pipe or 'hoseline 12 extends from this tank D to the nip- -ple '9. A bolt 13 is secured to the upper plate A in such a relation that it forms a end,

tweight.

Specification of LettersPatc-nt. r 191'?, f 'Appiieaaonineaaugust1s, 1914. seriarnassasra f i H u means of attachmentl lfor ,theyV In' use thespring` would-,be Qonnectedjn any .suitable pressure., ass-the, `circumstances may require. The air flows through the tube l2, and fills .the casingx-B 'whichsupportsthe As an obstruction is encountered, o-r a shock is transmitted to the spring, the stem is brought nearer to the top plate A, and the casing B is deformed, decreasing its cubic area and causing a part of the air to be displaced therefrom, and forced back through the tube l2 to the air tank D. This relieves any extraordinary compression in the casing B, and as the air forced therefrom mingles with the total volume in the air tank, there is no perceptible compression and hence no force to re-act and no recoil.

When the abnormal load is removed and the blow is spent against the increased area, the cushion will reform at practically the same pressure, and consequently the same air- -eushion effect will be maintained on the re- Y cheaply manufactured, and readily applied to take the place of the Ordinary metal spring now in general use.

It will be seen that slight changes might i be resorted to in the form and arrangementV derside of the annular ange of the flexible casing, and an internal disk having a downwardly projecting flange which forms an internal lateral support for the flexible casing7 and means for drawing the collar and the top plate toward each other in an air-tight embrace of the opposite faces of the interposed Hange of the flexible casing.

2. A pneumatic spring comprising a flexible casing having an annular ange at the upper edge thereof, a top plate having a flanged edge adapted to receive the flanged edge of the flexible casing, a collar having an upturned flange adapted to fit within the flange and embrace the under-side of the annular flange yof the flexible casing, means for drawing the collar and top plate toward each other in an air-tight embrace upon the opposite faces of the interposed ange of the flexible casing, a stem, a hollow boltV extending through the flexible casing into the stem, nuts on the bolt for securing the flexible casing to the stem, an air-tank and hose extending from the air-tank to the hollow bolt, whereby vconnection is established between the flexible casing and the air-tank.

In testimony whereof I aflix my signature, in the presence of two witnesses.

ERNEST D. FOSTER. Witnesses: Y

OLIVER B. GRAHAM, ERNEST H. BUSH.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents.

Washington, D. C. 

